Estuarine Habitat Use by Juvenile English Sole and Relationships to Recruitment

English sole (Pleuronectes vetulus) is one of a few commercially important marine fishes on the Pacific coast of North America that utilize estuarine areas as nurseries for juvenile stages.  English sole recruitment has been linked to environmental conditions occurring during their 6-10 week pelagic egg and larval stages, prior to their appearance in nursery estuaries during their first summer. Recruitment has also been linked to the amount of habitat available for settlement within estuaries.  The purpose of this study was to determine spatial patterns of juvenile English sole residence in Pacific coast estuaries over a number of years and specifically identify the important habitats they use within coastal estuaries.  Since movement into estuaries can occur over a prolonged spring period, multiple size classes of fish can occur in these nearshore habitats.  Regardless of size, juvenile English sole utilize lower side channel locations at significantly higher densities than other estuarine areas and show relationships with environmental conditions in the estuary.  These data analyses also suggest a carrying capacity may exist for English sole in nursery estuaries.  Since the resources in nursery areas can restrict density, the habitats available may be important determinants of recruitment to the adult population supporting an important offshore commercial fishery.  A population model determined that production of English sole from the combined Oregon and Washington estuaries was consistent with the estimates of the adult stock and the observed catch from 1956-1997.  The results suggested that the English sole population on the Oregon-Washington shelf could potentially be supported solely by estuarine production.  Potential changes in the abundance and quality of nearshore, estuarine habitats can thus directly affect the abundance of this stock and the commercial fishery.